Apparent oliguria following urological surgery.

Oliguria is a common feature of acute kidney injury (AKI), but should be interpreted in the context of other biochemical markers when diagnosing and monitoring AKI or considering the need for renal support. We report an unusual case of apparent severe oliguria arising as a result of complex urological pathology and discuss how an understanding of creatinine kinetics raised suspicions of an alternative diagnosis. We discuss the problems caused by an over-reliance on urine output or serum creatinine alone when diagnosing and staging AKI and highlight the need for a more holistic approach.

Diagnosis and management of acute kidney injury: deficiencies in the knowledge base of non-specialist, trainee medical staff.

Enhanced education has been recommended to improve non-specialist management of acute kidney injury (AKI). However, the extent of any gaps in knowledge has yet to be defined fully. The aim of this study was to assess understanding of trainee doctors in the prevention, diagnosis and initial management of AKI. An anonymised questionnaire was completed by hospital-based trainees across Newcastle Renal Unit's catchment area. Responses were evaluated against a panel of pre-defined ideal answers. The median score was 9.5 out of 20 (n = 146; range 0-17) and was lower in more junior trainees. Fifty percent of trainees could not define AKI, 30% could not name more than two risk factors for AKI and 37% could not name even one indication for renal referral. These serious gaps in knowledge highlight the need for enhanced education aimed at all training grades. Organisational changes may also be required to optimise patient safety.

Posttransplant lymphoproliferative disorder presenting as multiple cystic lesions in a renal transplant recipient.

We report a case of a 67-year-old man who experienced allograft dysfunction following a renal transplantation from a donation after cardiac death. The postoperative course was initially complicated by episodes of E. coli urinary sepsis causing pyrexia and a raised creatinine level. Ultrasound scanning 5 weeks posttransplant revealed mild hydronephrosis with several parenchymal cystic areas measuring up to 2 cm with appearances suggestive of fungal balls. Aspirated fluid again grew Escherichia coli, and this was treated with the appropriate antimicrobial therapy. The patient continued to have episodes of culture-negative sepsis; therefore, a computed tomography scan was performed 6 months posttransplant, which revealed multiple lesions in the renal cortex as well as liver and spleen. Subsequent biopsy revealed an Epstein-Barr virus-driven lymphoproliferation consistent with a polymorphic posttransplantation lymphoproliferative disorder (PTLD). This rare case of PTLD presenting as multiple renal, hepatic and splenic lesions emphasizes the need for a high index of clinical suspicion for this condition. Abnormal para-renal allograft masses should be biopsied to allow swift and effective management of a disease that can disseminate and become significantly more challenging to manage.

Necrotising otitis externa: an unusual cause of cranial nerve palsy in a diabetic haemodialysis patient.

We present an unusual case of necrotising otitis externa (NOE) causing a lower motor neurone facial nerve palsy in a patient with diabetes mellitus and receiving maintenance haemodialysis for end-stage renal disease (ESRD). Pseudomonas aeruginosa is the most common pathogen isolated in NOE, although our case involved the non-typical pathogens Aspergillus flavus and Proteus mirabilis. We discuss the need for diagnostic rigour and the importance of considering atypical infective pathology in patients with ESRD or diabetes mellitus. We review NOE with reference to causative agents, imaging strategies, prognostic indicators and treatment.

Theory and practical application of blood-based renal replacement therapy.

The term renal replacement therapy incorporates three modalities that control or correct biochemical and fluid disturbances of renal failure. Peritoneal dialysis and renal transplantation are two forms of renal replacement therapy that are outside the remit of this article. This review focuses upon the third group which are blood-based and involve direct treatment of a patient's blood in a closed, extracorporeal circuit. They provide renal replacement for end-stage renal failure and during periods of severe acute kidney injury, and also for non-renal indications such as the management of drug overdoses. Blood-based renal replacement therapies are often loosely referred to as 'haemodialysis', although this is only one of a range of treatments. This article outlines the theory and practical applications of these treatments.

Patient flow from critical care to renal services: a year-long survey in a critical care network.

BACKGROUND: The NSF for Renal Services stresses the importance of collaboration between renal services and critical care networks in managing patients with acute renal failure in the most clinically appropriate setting. Anecdotal evidence in our region suggested that some patients were remaining on critical care inappropriately because of a lack of capacity for step-down care in local renal units. AIM: To determine the number of extra days patients spend on critical care receiving single-organ renal support before transfer to a renal unit. DESIGN: Prospective, multi-centre, service evaluation. METHODS: Prospective data were collected over a one-year period by either daily telephone calls or bedside review. Follow-up data were retrieved from electronic and patient records. RESULTS: Five hundred and forty-two patients received renal replacement therapy (RRT) in critical care. With 68 (12.5%) patients already receiving RRT for end-stage renal failure, this gave an incidence of new RRT on critical care of 234 per million population per year. The median duration of RRT on critical care was 4 days (range 1-30). One hundred and twenty-seven patients (23%) were discharged from critical care still requiring RRT. A period of single-organ renal support (median 2 days, range 1-8) was provided to 74 of these patients (58%) using 113 critical care bed days. DISCUSSION: Over half of patients receiving RRT on discharge from critical care in our network received a short period of single-organ renal support before step-down. This may represent either delayed discharge from critical care or a potential opportunity for care in an alternative high-dependency facility.

How we estimate GFR--a pitfall of using a serum creatinine-based formula.

Chronic kidney disease (CKD) is defined using the estimated glomerular filtration rate (eGFR). This has led to a large increase in the diagnosis of CKD in the United Kingdom, the majority of which is in its earlier stages and is detected in non-hospital settings. It is important to be aware that eGFR calculations will reflect inaccuracies in the measured serum creatinine, as the latter is an important component of the calculation. We report a case in which a patient with high muscle-mass who had consumed large quantities of a creatine-containing nutritional supplement presented with apparently reduced renal function on the basis of the serum creatinine and therefore also the eGFR calculation (MDRD equation). Creatine is an amino acid which is a precursor of creatinine, and is known to transiently increase serum creatinine. 6 weeks after discontinuing creatine ingestion, serum creatinine had fallen but still gave rise to an apparently abnormal calculated eGFR. In fact, renal function was shown to be normal when estimated using 24-hour urinary creatinine clearance. This case demonstrates that the upper extreme of muscle mass and ingestion of creatine can affect not only serum creatinine but also the calculated eGFR. Knowledge of common confounding factors and their effects on serum creatinine and eGFR will allow appreciation of the limitations of these measures of renal function, and can prevent unnecessary over-investigation of such patients.

Rapid onset intratubular calcification following renal transplantation requiring urgent parathyroidectomy.

BACKGROUND: Secondary hyperparathyroidism is a common complication of end-stage renal disease often requiring parathyroidectomy. Renal transplant with the restoration of normal renal function often allows resolution of hyperparathyroidism, avoiding the need for parathyroid surgery. However, a proportion of patients with hyperparathyroidism become overtly hypercalcemic after renal transplantation which poses management dilemmas between medical and surgical treatment. CASE: We present the case of a 48-yearold man with end-stage renal failure known to have secondary hyperparathyroidism who received a living related renal transplant. Postoperatively he developed prompt hypercalcemia, polyuria, polydipsia and rapid onset intratubular calcification, leading to acute tubular necrosis diagnosed on renal biopsy on Day 7 post transplantation. He underwent surgical parathyroidectomy with resolution of his hypercalcemia and improved renal transplant function. DISCUSSION: This case emphasizes the need for good management of secondary hyperparathyroidism together with close surveillance of PTH in patients awaiting renal transplantation. With good renal transplant function hyperparathyroidism usually resolves. Posttransplant surgical parathyroidectomy should be reserved for severe progressive end organ damage.

Acute renal failure due to mantle cell lymphoma--a case report and discussion of the literature.

Acute renal failure secondary to lymphomatous infiltration of the kidneys is a rare manifestation raer mantle cell lymphoma (MCL). We present the case of a 76-year-old gentleman with acute renal failure an a background of previously treated low grade non-hodgkin lymphoma. At the time of presentation he complained only of mild lethargy und had no lymphadenopathy or organomegaly. Renal ultrasound revealed bilaterally enlarged kidneys and renal biopsy confirmed MCL. Mantle cell lymphoma runs an aggressive course and accurate diagnosis is very important in guiding appropriate treatment. This case demonstrates the importance of renal biopsy in the diagnosis of renal lymphomatous infiltration but also highlights the potential utility of histological examination in guiding targeted therapy.

A preliminary survey of bacterial contamination of the dialysate circuit in continuous veno-venous hemodialysis.

AIMS: The problem of dialysate bacterial contamination has not been defined in continuous renal replacement therapy. We assessed the bacterial integrity of source bicarbonate dialysate (study 1) and the continuous veno-venous HD (CVVHD) bicarbonate dialysate circuit (study 2). METHODS: Study 1: 50 ml dialysate were collected from 41 bags randomly selected from 150 consecutively made dialysate bags, immediately after manufacture or after 24, 48 or 72 h. Study 2: 10 ml dialysate were drawn from 4 sample points ranged along the dialysate circuit in 18 therapies (mean duration 119.5 +/- 72.0 h). All points were sampled at therapy start then daily, bar the proximal point which was sampled after each dialysate bag change. All dialysate samples underwent Gram stain and aerobic/anaerobic culture. Samples over 10 ml were cultured after centrifugation (15 min, 4,000 rpm). A disseminated contamination (DC) involved > or = 1 sample point at a time and/or was sustained over time. RESULTS: Study 1: One bag was culture-positive (staphylococcal/diphtheroid growths; 48-h sample). Study 2: Six DCs developed in 6 therapies (1 at therapy end, 5 sustained to therapy end (duration 57.25 +/- 45.95 h), 5 with Gram-negative bacilli, all involving reported growths of > or = 1,000 cfu). Dialyzer-inclusive dialysate circuit changes were more frequent in non-DC therapies (change rate: DC, 0.08 +/- 0.12/day, non-DC, 0.34 +/- 0.23, p = 0.02, permutation tests with general scores) but did not entirely prevent DC or alter it once underway. CONCLUSIONS: Sustained bacterial contamination of bicarbonate-based CVVHD is common and could relate to the completeness of dialysate circuit change. The importance of technique and regular quality control is highlighted.

A fractional dialysate collection method to estimate solute removal in continuous venovenous hemodialysis.

BACKGROUND: Fractional direct dialysis quantification (fDDQ), whereby a known proportion of dialysate effluent is sampled, can reliably estimate total solute removal in intermittent hemodialysis (IHD). Our study aimed to develop and test the technique in continuous venovenous hemodialysis (CVVHD). METHODS: Twenty dialysate collections (mean duration 23.5 hours, range 17.25 to 26.6) were performed in 12 patients on CVVHD. An infusion pump diverted 10% of the total effluent volume to the fractional collection (fc), the remainder being channeled into the bulk collection (bc). Both fc and bc were collected on ice and assayed for urea nitrogen (UN) and creatinine (Cr). Actual solute removal (ASR) was calculated from the measured effluent volume and solute concentrations of the fc and bc. Estimated solute removal (ESR) was calculated from the product of the fc solute concentration and effluent volume. All fc/bc samples in 15 out of 20 collections underwent gram stain and aerobic/anaerobic culture. RESULTS: Bland-Altman analyses suggested good agreement between ASR and ESR [absolute values of percentage differences: 95% CI = 1.73, 5.17% (UN); 1.88, 4.31% (Cr)]. Favorable concordance correlation coefficients confirmed this [rc = 0.995 (UN), 0.997 (Cr)] and were apparently unaffected by heavy pseudomonal growths in 4 out of 7 culture positive collections [rc = 0.997 (UN), 0.997 (Cr); culture negative (N = 8), rc = 0.996 (UN), 0.997 Cr)]. CONCLUSION: fDDQ, using 24-hour, pump-assisted, cooled fractional dialysate sampling reliably estimates total solute removal and provides a practical alternative to total dialysate collection in assessing delivered dialysis dose.